1. Field of the Invention
The present invention relates to an arrangement for mounting to a mother board a display device which comprises a plurality of light sources and a reflecting case formed with window holes each corresponding to one of the light sources, for displaying symbols such as letters by turning on selected light sources. Further, the present invention relates to a method for mounting such a display device to a mother board.
2. Background Art
Conventional display devices of the above type include a seven-segment LED display device in which seven, bar-shaped, light emitting elements are disposed in a pattern of a numeral 8 for displaying a desired numeral. Also included is an eight-segment LED display device which is a seven-segment device added with another light emitting element representing a decimal point. Further included is a dot-matrix type LED display device in which a plurality of dots each made of a light emitting element are disposed in a matrix pattern or displaying a symbol such as a numeral or a character. FIGS. 1 and 2 show a seven-segment LED display device. Not limited by the illustrated display device, any of the above display devices is mounted on a mother board, and is supplied with electric power through the mother board.
As shown in FIGS. 1 and 2, the illustrated display device 1 comprises a substrate 13 having two end portions each formed with a plurality of recesses 12e. The substrate 13 is formed with a plurality of light source pads 12a each mounted by an LED light source 17, and a plurality of wirebonding pads 12b each connected to one of the light sources 17 via a wire 18. Each pair of the light source pad 12a and the wirebonding pad 12b is formed as a continuous wiring pattern reaching one of the recesses 12e each formed with a terminal portion 12c made of a conductive material. Conventionally, with the above arrangement, mounting of the display device 1 to a mother board 2 is made as shown in FIG. 8. Specifically, the display device 1 is lowered onto the mother board 2, and each of the terminal portions 12c is bonded to a terminal portion in the mother board 2 by solder H for example. More specifically, each of the terminal portions 12c of the diasplay device 1 or each of the terminal portions of the mother board 2 is coated with solder in advance, then the display device 1 is aligned with and lowered on the mother board. Next, the solder H is re-melted, and then cooled to solidify.
However, as clearly shown in FIG. 8, the display device 1 projects out of a surface of the mother board 2, posing problems to be described below.
Specifically, when the mother board 2 is to be assembled to an apparatus, the apparatus must be designed taking the thickness of the projecting display device 1 into consideration. The apparatus must be large enough to include the projection by the display device 1, which goes against a market demand for a thinner product. Further, when handling the mother board 2, the display device 1 is apt to interfere with other members or components to the extent that the display device 1 projects out. Thus, the display device is more susceptible to external impact, and should there be such an external impact, prone to a trouble such as a shorted circuit between the mother board 2 and the display device 1.